1. Field of the Invention
The present invention pertains to the field of optoelectronics. The invention more particularly concerns a pluggable transceiver array having optical multiplexing and de-multiplexing features.
2. Discussion of the Background
During the late 1990s and into the early 2000s, optical fiber based data transmission systems flourished. Users of routers and servers or other host devices connect the routers and servers to each other with optical fiber so that the routers and servers can be placed several meters to several kilometers apart. Internally, routers and servers transmit data signals electrically on, typically, copper based conductors. Thus a transducer is required between the optical fiber and the copper conductor so as to convert an optical data signal to an electrical data signal, and to convert an electrical data signal to an optical data signal. Such transducers include GBIC (Gigabit Interface Converter) and SFFP (Small Form Factor Pluggable) transceivers that are well known in the art U.S. Pat. Nos. 6,142,802; 6,267,606; 6,335,869; and 6,350,063 show examples of pluggable transceivers. U.S. Pat. Nos 6,142,802; 6,267,606; 6,335,869; and 6,350,063 are hereby incorporated herein by reference.
As the use of optical fiber and transceiver based systems expanded, new host devices were installed in data center and central office locations. The host devices were connected to each other via optical fibers. The optical fibers were laid over wide areas so as to accommodate metropolitan communication systems which typically involve extensive routing and switching of various nodes (host devices) positioned within optical fiber rings. Since, typically, each transceiver is associated with two optical fibers (one optical fiber carries outgoing data and the other optical fiber carries incoming data) the number of optical fibers populating the host device greatly grew. Then, it became impracticable to lay more optical fiber. Therefore, to increase the bandwidth, wavelength division multiplexing (WDM) was developed so that the transmission capability of a single optical fiber was multiplied. Thus, the preexisting optical fiber which had been laid can now transmit more bandwidth. In such a scenario, more host devices can be brought on-line without more optical fiber being laid. One such wavelength division multiplexing (WDM) system is disclosed in U.S. Pat. No. 6,339,663. U.S. Pat. No. 6,339,663 is hereby incorporated herein by reference.
In an effort to take advantage of the wavelength division multiplexing (WDM) technology, one manufacturer of servers and routers offers a solution which reduces the number of optical fibers running between respective host devices while maintaining the use of pre-existing host devices and no new optical fiber need be laid. Therefore, the solution is transparent to the host devices. In one example, the solution consists of four GBICs, eight optical fiber jumpers cables, and a multiplexer/de-multiplexer box. Bach GBIC converts an optical data signal at a specified frequency, where each of the four GBIC are tuned to a different frequency. The four GBICs are plugged into the host device and each GBIC is linked to the multiplexer/de-multiplexer with two optical fiber jumper cables. The outgoing optical data signals of each of the GBICs are multiplexed by the multiplexing function of the multiplexer/de-multiplexer and all four of the optical data signals exit the multiplexer/de-multiplexer along a single optical fiber. Likewise, the incoming multiplexed system optical data signals carried by a single optical fiber are separated into four optical data signals by the de-multiplexing function of the multiplexer/de-multiplexer. Each of the four optical data signals has a different frequency. Each of the different frequencies of optical data signals or colors of light is connected to the appropriately tuned GBIC for conversion to an electrical data signal.
FIG. 1 shows a schematic of such a system, where the host device is identified by numeral designator 1, the transceivers are identified by numeral designators 2, 3, 4, and 5, the optical fiber jumper cables are identified by numeral designators 6, 7, 8, 9, 10, 11, 12, and 13, the multiplexer/de-multiplexer is identified by numeral designator 14, the multiplexing portion is identified by numeral designator 15, the de-multiplexing portion is identified by numeral designator 16, the system input optical fiber is identified by numeral designator 17, and the system output optical fiber is identified by numeral designator 18. The arrows show the flow directions of the optical data signals.
An advantage of the above-identified solution is that the number of optical fibers running between two host devices is reduced by a factor of four. However, the original problem remains between the host device and the multiplexer/de-multiplexer, namely, that the each transceiver or GBIC has two optical fibers running between it and the multiplexer/de-multiplexer. Additionally, a new element has been added to the users"" inventory, the multiplexer/de-multiplexer box. Furthermore, the multiplexer/de-multiplexer box occupies valuable real estate in or near the host device thus further crowding data centers and central offices. Thus, the above-identified solution does not reduce the number of optical fibers projecting out of the host device via the transceivers or host devices or other optical transducers. Therefore, users of host devices such as servers and routers seek a solution to reducing the number of optical fibers projecting from the host devices so that the management of the optical fibers is eased while maintaining use of preexisting host devices.
Therefore, it is an object of the invention to provide a device which includes the transceivers, the optical fibers or waveguides, the multiplexer, and the de-multiplexer, in a single body or housing or structure, where the device is pluggable into a host device or system.
It is another object of the present invention to provide a device which eliminates the need to lay new optical fibers between existing host devices.
It is yet another object of the present invention to provide a device which can self-align multiple members or transceivers relative to the housing of the device and to the host device to which it is plugged.
It is still yet another object of the present invention to provide a device which lowers the power loss of a multiplexing/de-multiplexing system by reducing the number connections between optical components such as receivers, transmitters, multiplexers, de-multiplexers, and optical ports.
In one form of the invention, the device includes a housing, a first member attached to the housing, and a second member attached to the housing. The first member is mounted to the housing so as to provide six degrees of freedom of motion for the first member relative to the housing upon insertion of the first member into a host device. The first member also has electrical contacts for plugging to or from complementary contacts of the host device. The second member is similarly attached to the housing as is the first member. The second member is also similarly constructed as is the first member. The housing includes two optical fiber ports.
In yet another form of the invention, the device includes a third member and a fourth member, where the third and fourth members are attached to the housing and are constructed similar to the first and second members.
In still yet another form of the invention, an optoelectronic transceiver is based upon the structure described in the first above-described device. The optoelectronic transceiver includes a multiplexer, a de-multiplexer, a first receiving optical subassembly, a first transmitting optical subassembly, a second receiving optical subassembly, and a second transmitting optical subassembly. The multiplexer has a first optical input, a second optical input, and a system optical output. The de-multiplexer has a system optical input, a first optical output, and a second optical output. The first receiving optical subassembly converts a first optical data signal at a first frequency to a first electrical data signal, and the first electrical data signal is electrically associated with the electrical contacts of the first member, and the first optical data signal is in optical communication with the first optical output of the de-multiplexer. The first transmitting optical subassembly converts a second electrical data signal to a second optical data signal, and the second electrical data signal is electrically associated with the electrical contacts of the first member, and the second optical data signal is in optical communication with the first optical input of the multiplexer. The second receiving optical subassembly converts a third optical data signal at a second frequency to a third electrical data signal, and the third electrical data signal is electrically associated with the electrical contacts of the second member, and the third optical data signal is in optical communication with the second optical output of the de-multiplexer. The second transmitting optical subassembly converts a fourth electrical data signal to a fourth optical data signal, and the fourth electrical data signal is electrically associated with the electrical contacts of the second member, and the fourth optical data signal is in optical communication with the second optical input of the multiplexer. The first optical data signal and the third optical data signal have different frequencies, and the second optical data signal and the fourth optical data signal have different frequencies. The multiplexer multiplexes the second optical data signal and the fourth optical data signal so as to allow both of the optical data signals to travel down the same optical fiber at the same time. The system output of the multiplexer is in optical communication with the multiplexed system output optical data signals. The multiplexed system output optical data signals are in optical communication with a first optical fiber port of the two optical fiber ports of the housing. The system optical input of the de-multiplexer is in optical communication with multiplexed system input optical data signals. The de-multiplexer separates the multiplexed system input optical data signals into the first optical data signal and the third optical data signal. The multiplexed system input optical data signals are in optical communication with a second optical fiber port of the two optical fiber ports of the housing
In another form of the invention, the optoelectronic transceiver, as described above, includes a third member, a fourth, member, and third and fourth transmitting optical subassemblies, and third and fourth receiving optical subassemblies. The multiplexer and de-multiplexer are constructed so as to accept two more optical inputs and optical outputs, respectively. Furthermore, the third and fourth members are similarly attached to the housing as are the first and second members. The third and fourth transmitting optical subassemblies are attached to the transceiver in a likewise manner as are the first and second transmitting optical subassemblies. The third and fourth receiving optical subassemblies are attached to the transceiver in a likewise manner as are the first and second receiving optical subassemblies.
In yet another form of the invention, the optoelectronic transceiver includes a structure, a first member mounted to the structure, a second member mounted to the structure, a multiplexer mounted to the structure, and a de-multiplexer mounted to the structure. The first and second members have respective electrical contacts for plugging into complementary contacts of a host device. The structure has two optical fiber ports for receiving two optical fiber connectors. The multiplexer has a system output which is in optical communication with a first optical fiber port of the two optical fiber ports of the structure. The de-multiplexer has a system input which is in optical communication with a second optical fiber port of the two optical fiber ports of the structure.
In still yet another form of the invention, the device includes a structure, a first member mounted to the structure, and a second member nounted to the structure. The first and second members have respective electrical contacts for plugging into complementary contacts of a host device. The structure has two optical fiber ports for receiving two optical fiber connectors.
In another form of the invention, the optoelectronic transceiver includes a structure, a first member mounted to the structure, a second member mounted to the structure, a multiplexer mounted to the structure, a de-multiplexer mounted to the structure, a first receiving optical subassembly, a first transmitting optical subassembly, a second receiving optical subassembly, and a second transmitting optical subassembly. The first member is mounted to the structure so as to provide six degrees of freedom of motion for the first member relative to the structure upon insertion of the first member into a host device. The first member also has electrical contacts for plugging to or from complementary contacts of the host device. The second member is similarly attached to the structure as is the first member. The second member is also similarly constructed as is the first member. The structure includes two optical fiber ports. The multiplexer has a first optical input, a second optical input, and a system optical output. The de-multiplexer has a system optical input, a first optical output, and a second optical output. The first receiving optical subassembly converts a first optical data signal at a first frequency to a first electrical data signal, and the first electrical data signal is electrically associated with the electrical contacts of the first member, and the first optical data signal is in optical communication with the first optical output of the de-multiplexer. The first transmitting optical subassembly converts a second electrical data signal to a second optical data signal, and the second electrical data signal is electrically associated with the electrical contacts of the first member, and the second optical data signal is in optical communication with the first optical input of the multiplexer. The second receiving optical subassembly converts a third optical data signal at a second frequency to a third electrical data signal, and the third electrical data signal is electrically associated with the electrical contacts of the second member, and the third optical data signal is in optical communication with the second optical output of the de-multiplexer. The second transmitting optical subassembly converts a fourth electrical data signal to a fourth optical data signal, and the fourth electrical data signal is electrically associated with the electrical contacts of the second member, and the fourth optical data signal is in optical communication with the second optical input of the multiplexer. The first optical data signal and the third optical data signal have different frequencies, and the second optical data signal and the fourth optical data signal have different frequencies. The multiplexer multiplexes the second optical data signal and the fourth optical data signal so as to allow both of the optical data signals to travel down the same optical fiber at the same time. The system output of the multiplexer is in optical communication with the multiplexed system output optical data signals. The multiplexed system output optical data signals are in optical communication with a first optical fiber port of the two optical fiber ports of the housing. The system optical input of the de-multiplexer is in optical communication with multiplexed system input optical data signals. The de-multiplexer separates the multiplexed system input optical data signal into the first optical data signal and the third optical data signal. The multiplexed system input optical data signals are in optical communication with a second optical fiber port of the two optical fiber ports of the housing.
Thus, the device of the invention is superior to existing solutions since the device is compact. The compact device integrates all of the stand-alone separate components and integrates them into a single device which is self aligning upon insertion into a router or server or other host device. Thus, the device of the invention is easy to use, occupies less space, has lower power losses, does not require new optical fibers to be laid between existing host devices, and is more cost effective than prior solutions.